Photoshop CS2 All-in-One Desk Reference For Dummies- P23

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Photoshop CS2 All-in-One Desk Reference For Dummies- P23

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Photoshop CS2 All-in-One Desk Reference For Dummies- P23:Barbara Obermeier is principal of Obermeier Design, a graphic design studio in Ventura, California. She’s the author of Photoshop Album For Dummies, coauthor of Adobe Master Class: Illustrator Illuminated, Photoshop 7 For Dummies, and Illustrator 10 For Dummies. She has contributed as coauthor, technical editor, or layout designer for numerous books. Barb also teaches computer graphics at Brooks Institute; the University of California, Santa Barbara; and Ventura College....

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  1. 638 Getting Four-Color Separations 7. When you finish making your selections, click Print. That’s all there is to it. If you want more information on printing, check out Book I, Chapter 3. For more explanation on color management, see Book II, Chapter 3. If all you want to do is print color prints on your desktop printer, I recom- mend starting off by choosing Document in the Print area and choosing Let Photoshop Determine Colors for Color Handling. If you have a little time and paper to burn, then print another copy by using Let Printer Determine Colors for Color Space. Do a side-by-side comparison to see which one looks superior. You can also crack the seal on the documentation that came with your printer for any recommendations. Getting Four-Color Separations It is necessary to color separate your image whenever you plan to print your image to an offset press. Your image must first be in CMYK color mode (choose Image➪Mode➪CMYK Color). Then the composite color image gets digitally separated into the four-color channels — cyan, magenta, yellow, and black — and is output. (These colors are also known as process colors.) Sometimes, the separation output is onto film, and sometimes, it is output directly to aluminum printing plates. The plates are put on an offset press, paper runs through each of the four inked rollers (cyan first, then magenta, yellow, and finally black), and out comes your composite image. Getting laser separations Before you take your image to a service bureau or offset printer to get color separations, it is wise to get what are called laser separations. Basically, you are color separating your image, not to film or plates, but to paper. If your image doesn’t separate to paper, most likely it won’t to film or plates, either. You can go back and and correct the problem, rather than pay upwards of $80 to $150 an hour to have the service bureau or offset printer correct it for you. Consider laser separations a cheap insurance policy. Follow these steps to get laser separations from your desktop printer: 1. Be sure your image mode is CMYK. If it isn’t, choose Image➪Mode➪ CMYK Color. I’m assuming your image is a four-color image. But it may also be a grayscale, duotone, tritone, or quadtone image, in which case no conver- sion to CMYK is necessary. (See Book II, Chapter 2, for more on modes.) If you’re new to converting RGB images to CMYK, don’t be surprised if your vibrant colors turn muddy and flat. This is because the gamut, a
  2. Getting Four-Color Separations 639 fancy word for range of color, for CMYK is much smaller than it is for Book IX RGB, and Photoshop converts colors that are out of the CMYK gamut to Chapter 1 their closest match. It’s a cold, harsh fact that we all have to live with. After the conversion, you have an image with four channels — Cyan, Prepping Graphics Magenta, Yellow, and Black, like the one shown in Figure 1-2. for Print Cyan Magenta Yellow Black Corbis Digital Stock Figure 1-2: Color images are separated into four process colors — cyan, magenta, yellow and black.
  3. 640 Getting Four-Color Separations 2. Choose File➪Print with Preview. In the Print dialog box, click More Options and select Color Management from the pop-up menu on the far left under the Preview window. 3. In the Print area, select Document. It should say U.S. Web Coated (SWOP) v2. 4. Select Separations from the Color Handling pop-up menu. This option prints each channel from the image to a separate plate, or in the case of laser separations, paper. 5. Select Output from the pop-up menu above the Print area, as shown in Figure 1-3. Then select additional options as you desire. Figure 1-3: When printing color separations, be sure and check the necessary options in the Output section of the Print with Preview dialog box.
  4. Getting Four-Color Separations 641 For general print options, see Book I, Chapter 3. For additional options, Book IX see Table 1-3. Chapter 1 Note that if you’re printing to a non-PostScript printer, some of these Prepping Graphics options may not be available. You see a preview of most of these options as you apply them to your file. for Print 6. Click the Print button. If all goes well, four pieces of paper, one for each of the four CMYK chan- nels, prints. If you’re printing a grayscale, duotone, tritone, or quadtone image, you get one to four pieces of paper, one for each color used. If that doesn’t happen, something’s amiss, and it’s time for troubleshoot- ing. Be sure to take these laser separations with you when you hand over your file to the service bureau or offset printer. Table 1-3 Output Options Option What It Does Recommendation Screen Creates a custom halftone Leave this set to Use Printer’s screen by changing the size, Default Screen. Let the service angle, and shape of the bureau or offset printer change halftone dots. it if necessary. Transfer Redistributes brightness levels I wouldn’t mess with this in your image. setting unless you’re a prepress professional. Interpolation Anti-aliases low-resolution Available only for PostScript images by resampling. Level 2 or laser printers. Leave it deselected. Calibration Bars Prints an 11-step grayscale bar Select this option. outside the image area to gauge how accurately the shades are being printed. When printing separations, this option prints a gradient tint bar and color bar. Registration Marks Prints crosshair and target Select this option. marks outside the image area, allowing you to line up the four plates or pages. Corner Crop Marks Adds crops marks at the corners Select this option. of the image to indicate where to trim the image. Center Crop Marks Adds crop marks at the center Select this option. of each side of the image to indicate where to trim the image. Labels Prints the filename and channel Select this option. name on each plate or page. continued
  5. 642 Creating Spot Color Separations Table 1-3 (continued) Option What It Does Recommendation Emulsion Down Emulsion is the side of the film Leave this option deselected for that is light sensitive. Allows laser separations. When the the film to be printed with the service bureau or offset printer emulsion side down. prints the separations to film or plates, it may select this option. Negative Prints black as white and white Leave this option deselected for as black, and every other color laser separations. When the inverts accordingly. service bureau or offset printer prints the separations to film or plates, it may select this option. Include Vector Data See the “Saving and Printing Leave this option selected if you Vector Data in a Raster File” have type or vector paths. section, earlier in this chapter. Encoding This option specifies the method Leave this option at the default of encoding used to send the of Binary. image to the printer. Creating Spot Color Separations Photoshop allows you to add separate channels for spot colors (see Book VI, Chapter 1, for more on channels), which can then be color separated. Spot, or custom, colors are premixed inks manufactured by various ink companies, the most popular in the U.S. being Pantone. A spot color is often used for a logo, type, or small illustration. Spot colors are also used when you need to apply metallic inks or varnishes to your print job. Spot colors can be used instead of, or in addition to, the four process CMYK colors. If you are delving into the world of spot colors, I highly recommend that you choose your color from a printed Pantone swatch book, available from Because your screen is an RGB device and you’re setting up your file for a CMYK output device, the colors you see on-screen do not match the colors that are ultimately on paper and at best are a ballpark match. For accuracy, you must select the colors from the printed swatch book. For more on working with color, see Book II, Chapter 3. Creating a spot channel Follow these steps to create a spot channel: 1. Create the graphic or type to which you want to apply the spot color on a separate layer.
  6. Creating Spot Color Separations 643 2. Ctrl+click (Ô+click on the Mac) on the thumbnail of the layer to select Book IX the graphic and then fill it with any solid color and an opacity of Chapter 1 100 percent. Prepping Graphics 3. With your selection active, choose Window➪Channels, and choose New Spot Channel from the Channels palette pop-up menu. for Print You can apply a spot color only to an active selection. It can’t be applied just to a layer. The New Spot Channel dialog box appears, as shown in Figure 1-4. Figure 1-4: Adding an additional color 4. In the Name text box, enter a separation in Photoshop requires creating a name for your spot color. In spot color channel first. the Ink Characteristics area, click the color swatch. I recommend naming it according to the spot color you want to use, such as Pantone 7417C. When you click the color swatch, the Color Picker appears. 5. Click the Custom button in the Color Picker and select your Pantone color from the Custom Colors dialog box that appears (see Figure1-5). Then click OK. Figure 1-5: Select an appropriate color for the Color Libraries dialog box.
  7. 644 Creating Spot Color Separations 6. In the New Spot Channel dialog box, select a Solidity value between 0 percent to 100 percent. A value of 100 percent represents an ink that is completely opaque, such as a metallic ink, which completely covers the inks beneath it. A value of 0 percent represents a transparent ink, such as a clear varnish. But the solidity value affects only the screen view and composite prints; it doesn’t affect the separations. It can be helpful to see where a “clear” varnish will print. 7. Click OK to close the dialog box. Your spot channel appears in the Channels palette and is filled in the image as well. I cre- ated a spot channel for my crest graphic and for the sushiko type (Pantone 7417C), as shown in Figure 1-6. In the printing process, spot colors are overprinted on top of the four-color image, as shown in Figure 1-7. That means that the spot color is applied at the end of the printing process and is printed over the other inks. This can sometimes cause lighter spot colors to darken somewhat. Figure 1-6: The Channels palette displays the spot channel. If you need your spot color graphic to knock out the under- lying image, create it in an illustration or page layout program. A knock- out is when a hole is left in the four-color image, and the spot ink then fills that hole. It does not print over the other inks. Converting an alpha channel to a spot channel If you want to convert an alpha channel to a areas containing nonwhite pixels (unselected to spot channel, select the alpha channel in the partially selected areas) to the spot color. Channels palette and choose Channel Options Choose Image➪Adjustments➪Invert to apply from the palette pop-up menu. Rename the the spot color to the white pixels or selected channel and select Spot Color. Choose a color areas of the alpha channel. For details on alpha from the Custom section of the Color Picker. channels, see Book VI, Chapters 1 and 3. Click OK. Note that Photoshop converts all
  8. Creating Spot Color Separations 645 Book IX Chapter 1 Prepping Graphics for Print Corbis Digital Stock Figure 1-7: Spot colors are often used for color critical logos that print on top of your image. 8. Save the image in the native Photoshop, Photoshop PDF, or Photoshop DCS 2.0 (Desktop Color Separations) format. If the image is being separated directly out of Photoshop, leave it as a PSD or PDF file. If you want to import it into a different program, such as PageMaker, InDesign, or QuarkXPress, you must save it as a DCS file. You also have to go through a few more hoops: If your image is a duotone, tritone, or quadtone image, you must first convert it to multi- channel mode with the Image➪Mode command.
  9. 646 Creating Spot Color Separations In the DCS 2.0 Format dialog box, make sure that the Include Halftone Screen and Include Transfer options are not selected. Import the image into your destination application and set your screen angles. Editing a spot channel After you create a spot channel, you can edit it. Select the channel in the Channels palette and use a painting or editing tool to paint with black, white, or any shade of gray, just as you would with an alpha channel. To change any of the options of the spot channel, double-click the spot channel thumbnail, or select it and choose Channel Options from the palette pop-up menu. Choose a different color or solidity.
  10. Chapter 2: Creating Contact Sheets, Picture Packages, and More In This Chapter Creating thumbnail catalogs with contact sheets Multiplying images into picture packages Using the Photomerge command Using the new Merge to HDR command Creating PDF presentations T he Contact Sheet II and Picture Package features are two common tasks that are tedious to perform manually. You can use these features to create documents of thumbnail images of groups of files and print multiple copies of an image on one sheet, much like the picture packages of 5 x 7s and wallet prints you order from school photogra- phers. Fortunately, the programming wizards at Adobe have made creating contact sheets and pic- ture packages easy, and this chapter leads you through the process. Cataloging with Contact Sheets If you’re not steeped in photographic darkroom lore (and fewer of us are, in these digital days), the term contact sheet might be fuzzy to you. The original purpose of contact sheets was to show the photographer a small image of each picture in a set of negatives so the photographer could compare the images, select which ones to print, and crop them with a grease pencil right on the contact sheet. Contact sheets also made a convenient way of filing away images. Today, we have more sophisticated ways of previewing and cataloging digi- tal images, including many different image-cataloging programs, such as Adobe’s own Photoshop Elements application. Even so, the Contact Sheet II
  11. 648 Cataloging with Contact Sheets automated tool in Photoshop works faster than database-type catalog pro- grams (which require you to enter keywords to sort and locate images) and performs useful tasks, such as the following: Prepare Photoshop documents so that you can store them, share them with others in digital form, or print them for distribution. Create ad hoc catalogs adeptly. Just copy the files you want to include to a folder and fire up the Contact Sheet II tool. Specify the number of rows and columns in your contact sheet, filling a sheet with only a few images (if that’s what you want) or packing dozens onto a single contact sheet. Automatically create multiple sheets if all the selected images don’t fit on a single sheet. Using Contact Sheet II With Contact Sheet II, you can create contact sheets that have many thumb- nail images on a single page. You can print the contact sheets or browse through them electronically. To create a contact sheet catalog of your own images, follow these steps: 1. Copy all the files you want to include in your contact sheet into a folder on your hard drive. 2. Choose File➪Automate➪Contact Sheet II. The Contact Sheet II dialog box appears, as shown in Figure 2-1. Note that you can find both the Contact Sheet II and Picture Package commands on the Tools➪Photoshop menu in Bridge. The Bridge makes for easy and quick visual selection of images to catalog or package. Check out Book I, Chapter 5, for more on Bridge. 3. In the Source Images area, click the Browse button (Choose on the Mac) and navigate to the folder containing the images you want to include. From the Use pop-up menu, you can also choose Selected Images from Bridge or Current Open Documents. 4. Select the Include All Subfolders check box if you want to include images contained in a folder’s subfolders. 5. Choose your desired unit of measurement from the Units pop-up menu. In the Width and Height boxes, enter the dimensions of the contact sheet document. Choose the default setting of 8 x 10 inches if you plan to print contact sheets on standard-sized paper.
  12. Cataloging with Contact Sheets 649 Book IX Chapter 2 Packages, and More Creating Contact Sheets, Picture Figure 2-1: The Contact Sheet II dialog box allows you to specify dimensions, resolution, color mode and columns and rows for your contact sheet. 6. Adjust the resolutions settings. A setting of 72 pixels/inch works well for contact sheets if all you want is just a quick-and-dirty look at them. Use a higher resolution if you want a sharper contact sheet. Remember, however that the file size will be larger. If you’re showing the contact sheets to a client or you want the individ- ual images to look crisp and clear, choose a higher resolution. Also, if you want the thumbnails to be larger (with fewer per page), choose a higher resolution and adjust the number of columns and rows in Step 10. Check out Book II, Chapter 1, for more recommendations on resolution settings. 7. Choose a color mode from the Mode pop-up menu. RGB works best in most cases. However, if your images are black-and- white photos, you can create smaller files by selecting the Grayscale option.
  13. 650 Cataloging with Contact Sheets Check your printer documentation to see the color mode recom- mended for printing color images. For more on color modes, see Book II, Chapter 2. 8. Select the Flatten All Layers check box if you want to create a contact sheet with a single layer in which all images and their captions (if any) are merged. This option significantly reduces the contact sheet’s file size. If you do not select this option, you end up with larger contact sheet files, but you have the additional flexibility of flattening the thumbnails yourself later both with and without captions. You can now start adjusting the layout. A Preview window at the right side of the dialog box shows roughly how the contact sheet will be laid out. 9. Select the Across First option from the Place pop-up menu to orient the thumbnails in rows. Down First orients the layout in columns. 10. In the Columns and Rows text boxes, enter the number of columns and rows. Beneath the small layout preview on the right side of the dialog box are the number of pages in your contact sheet, the total number of images, and the largest possible size of each image. If you plan to print such a maxi-thumbnail contact sheet, choose a higher resolution (such as 150 to 300 pixels/inch) sharper thumbnails. 11. Choose the spacing you want between the images. Select the Auto-Spacing option to have the default distance of .014 inches vertically and horizontally between each thumbnail option. Deselect the option to enter a custom distance. Select the Rotate For Best Fit option to have Photoshop rotate the thumbnails if necessary to accommodate a better fit based on your specifications. 12. Choose the Use Filename as Caption option to identify each image easily. You can also select the Font and Font Size from the option lists. 13. Click OK to create your contact sheet. If you change your mind, press the Esc key to quit. Figure 2-2 shows a contact sheet with five rows and four columns. Photoshop creates as many pages as necessary to include all the selected images. This can take a few minutes.
  14. Pretty as a Picture Package 651 Book IX Chapter 2 Packages, and More Creating Contact Sheets, Picture Figure 2-2: A digitally created contact sheet. Pretty as a Picture Package If you remember having your class pictures taken as a child or have ever gone to a retailer or professional photographer’s studio, then you have prob- ably seen the contact sheets that come from these photo sessions. You pur- chase one of those special deals and wind up with, say, an 8-x-10-inch print, two 5 x 7s, four 4 x 5s, and eight wallet-sized shots. The number of pictures you get at each of these dimensions isn’t pulled out of a hat. That’s the number of images at a given size that can fit on a single 8-x-10-inch sheet of photographic paper. Photofinishers have automated printers that can expose those duplicates onto a standard-sized section of a roll of photographic paper, which is then processed and cut apart by mechanized equipment. Photoshop can perform much the same magic with your own photos, creat- ing image documents that you can then print as your own picture packages.
  15. 652 Pretty as a Picture Package This is much easier and faster than you cropping and pasting multiple copies of images onto a single document. Just follow these steps to create your own picture package: 1. Open the picture you want to use for your picture package in Photoshop. If you want to create multiple picture packages of different images using the same parameters, copy the images to a single folder. You have your choice of using files in a folder, an opened file, a specific file, or selected files in Bridge. 2. Choose File➪Automate➪Picture Package. The Picture Package dialog box, shown in Figure 2-3, appears. Again, remember that you can also choose this command from within Bridge. 3. In the Source Images area, select Frontmost Document to create the pic- ture package from the image that is currently selected in Photoshop, or choose File and select a single file from your hard drive. Click Browse (Choose on the Mac) to navigate to files or folders. If you select Folder to create picture packages from all the files in a folder, all the picture packages must use the same parameters that you enter in the Picture Package dialog box. You can also use images that you have preselected from the Bridge. 4. If you’d like to include more than one picture in a picture package, such as I have Figure 2-3, click a sample thumbnail in the Layout area of the dialog box. A Select an Image File dialog box appears. 5. Find the image you want to substitute and click it. The image appears in the thumbnail you chose in Step 4. 6. Repeat to insert other images in the picture package. 7. Choose a setting for Page Size from the list. In most cases, you’ll want to use 8 x 10 inches. You can also select 10 x 16 inches or 11 x 17 inches if you have a printer that can handle larger sheets of paper. 8. Choose a layout. You can fill an entire sheet with only one size photo, if you like, such as two 5-x-7-inch pictures or eight 2.5-x-3.5-inch pictures. Or you can select one of the other combinations, such as two 4 x 5s, two 2.5 x 3.5s, or four 2-x-2.5-inch photos. 9. Adjust the resolution settings. The default value is 72 pixels/inch. You’ll probably want a higher resolu- tion, such as 300 pixels/inch if you plan to print the picture package.
  16. Pretty as a Picture Package 653 Book IX Chapter 2 Packages, and More Creating Contact Sheets, Picture Figure 2-3: The Picture Package feature enables you to create print layouts that rival professional photo studios. Check your printer documentation to see the recommended resolution. Also check out Book II, Chapter 1, for more on recommended resolution settings. 10. Choose a color mode from the Mode pop-up menu. RGB is the best choice in most cases. However, if your images happen to be black and white, you can create smaller, more compact picture package files by selecting the Grayscale option. Check your printer documentation. 11. Select the Flatten All Layers check box to create a picture package with a single layer in which Photoshop merges all images and their labels (if you choose to apply them). 12. If you want to apply some text, you can do it in the Label area of the dialog box. Most picture packages don’t require text descriptions, but you can choose content such as Filename, Copyright, Credit, and so on. 13. Select Custom Text from the Content pop-up menu to type your own text. 14. Adjust the font settings, position the text, and rotate the text to your heart’s content. Use the Opacity drop-down list to adjust the type’s opacity.
  17. 654 Using the Photomerge Command 15. Click the Edit Layout button to further customize your layout. In the dialog box, enter a name for your layout. Choose a size from the Page Size menu or enter dimensions in the Width and Height boxes. Choose a unit of measurement. In the Grid area, check the Snap To option to show a grid to help position your image and then specify the size of your grid increments. Click the placeholders, which may or may not contain images, and drag them to your desired location within the page. You can also reposition a placeholder by entering values in the X and Y boxes. Drag a handle to resize the placeholder or enter dimen- sions in the Width and Height boxes. Note that if you resize a place- holder with an image in it, the image snaps within the placeholder. Click the Add Zone button to add another placeholder. Click Delete Zone or Delete All to delete placeholders. When you are satisfied with your layout, click the Save button. 16. Click OK to create the picture package, ready for printing. Using the Photomerge Command The Photomerge command allows you to combine multiple images into one continuous panoramic image. For example, you can take several overlapping photos of a mountain range and put them together into one panoramic shot, as shown in Figure 2-4. Figure 2-4: The Photomerge command enables you to combine multiple images into one continuous panoramic shot. If you know you ultimately want to create a Photomerge composition, you can make things easier by making sure that when you shoot your photos, you overlap your individual images by 15 to 40 percent, but no more than 70 percent. Adobe also recommends avoiding using distortion lenses (such as fish-eye) and your camera’s zoom setting. Finally, try to stay in the same
  18. Using the Photomerge Command 655 position and keep your camera at the same level for each shot. Using a Book IX tripod and rotating the head can help you achieve this consistency. Chapter 2 Packages, and More Here are the steps to assemble your own Photomerge composition: Creating Contact Sheets, Picture 1. Choose File➪Automate➪Photomerge. You can also select your desired source images and choose Automate Photomerge from the Bridge menu. Using the Bridge method is a time- saver because you can quickly and visually select your images. 2. In the first Photomerge dialog box, choose your source files. You can select from Files (uses individual files you choose), Folder (uses all images in a folder), or Open Files (uses all currently open files) from the Use pop-up menu. Click the Browse button to navigate to your desired files or folder. If you want to delete a file from the list, select it and click Remove. 3. From the list of files, select the ones you want to merge. Select the Attempt to Automatically Arrange Source files option to direct Photoshop to try to compose the panorama automatically. Click OK. Photoshop opens and assembles the source files to create the composite panorama. 4. Photoshop alerts you if it cannot automatically composite your source files. You then have to assemble your images for yourself, as shown in Figure 2-5. Figure 2-5: Assemble images automatically or manually.
  19. 656 Using the Photomerge Command To manually assemble your composition, drag the image thumbnails from the lightbox area onto the work area with the arrow. Or simply double- click on the lightbox thumbnail to add it to the composition. You can also drag an image back into the lightbox to remove it. In addition, you can position the images or rearrange their order also using this same tool. Use the Rotate Image tool, the Zoom and Move View (more commonly known as the Hand tool) tools, and the Navigator view box to zoom in and out of your composition. See Book I, Chapter 5, if you need more details on using these tools. Select the Snap to Image option to have Photoshop automatically snap overlapping images into place. 5. To adjust the Vanishing Point, first select the Perspective option in the Settings area. Then, click your desired image with the Set Vanishing Point tool, which you can select from the Photomerge Tools palette on the left. Photoshop then changes the perspective of the composition. By default, Photoshop selects the center image as the Vanishing Point (look for the turquoise border). If needed, you can move the other images. Note, however, that when you select the Perspective setting, Photoshop links non-Vanishing Point images to the Vanishing Point image. To break the link, click the Normal setting button or separate the images in the work area. You can also drag the Vanishing Point image back into the lightbox. 6. Adjust the blending of the composition. Choose Cylindrical Mapping to reduce the bowed distortion you can get when you add perspective to your composition. (Note that you must select Perspective in the Settings area in order to apply cylindrical mapping.) Select Advanced Blending to correct the color differences that can occur from blending images with different exposures. Photoshop then blends the colors and tones. Click Preview to view your settings. Click Exit Preview to return to the Edit mode. You can also view the results in the final, rendered image. 7. Select the Keep As Layers option to save each image in the composite as an individual layer. 8. Click OK to generate the composite panorama as a new Photoshop file, which opens in Photoshop. Or click Save Composition to save the composite as a .pmg (Photomerge format) file, which you can later open in the Photomerge dialog box. To open a previously saved composite (.pmg file), click the Open Composition button in the Photomerge dialog box.
  20. Using the Merge to HDR command 657 Using the Merge to HDR command Book IX Chapter 2 Have you ever caught an early matinee and emerged mole-like from the pitch Packages, and More black theatre into the bright light of high noon only to have to squint for a Creating Contact Sheets, Picture while because your eyes burned? Or on the flip side, have you blindly tum- bled into your seat, popcorn scattering all over the aisle, into your seat in that same darkened theatre because you just came in from the bright day- light? In both cases, your eyes needed some time to adjust to the abrupt change from extreme dark to extreme light and vice-versa. Cameras suffer from the same problem. But while our eyes can eventually adapt to varying brightness levels, cameras and devices, such as computer monitors and scanners, can only capture a fixed dynamic, or tonal, range. In digital imaging tech talk, dynamic range is the ratio of the darkest and brightest values a device can capture simultaneously. In the past, digital photography afficionados were hindered when performing higher-end image editing tasks in Photoshop because they were forced to work within a limited dynamic range. Not anymore. Photoshop CS2 now pro- vides support for High Dyanamic Range (HDR) images. HDR images, which contain 32-bits of data per channel, are superior because they can capture a much larger dynamic range — in fact they are able to represent the entire dynamic range of the “real world.” Photographers can now take multiple exposures of an image and then later merge those multiple exposures into a single photo in Photoshop, thereby capturing the entire dynamic range into a single HDR image. Although you can use the Merge to HDR command on 8- or 16-bit images, be aware that only 32-bit images can store all the HDR data. Adobe offers a few tips to maximize your success with the Merge to HDR command: Use a tripod when shooting multiple exposures of the same scene to ensure you’re capturing the exact same shot each time. Make sure you take enough shots to cover the entire dynamic range of your subject. Shoot for a minimum of three, but try for five to seven, if not more. Vary the shutter speed to create different exposures, instead of your aperture or ISO, which can cause noise, vignetting, and altering of depth of field. Make sure the exposure difference between the shots is one or two Exposure Value (EV) steps apart. Use one or two f-stops apart as a guide. Don’t vary the lighting in the shots. Don’t shoot anything that is moving. The scene needs to be static.
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